In general, a compressor is a device for converting a mechanical energy into a compression energy of a fluid. And, depending on a compression method, a freezing compressor is classified into a reciprocating compressor, a scroll compressor, a centrifugal compressor and a rotary compressor.
The applicant of the present invention has filed an application for a development of a compressor with Z-plate with a novel conception, that can be classified as a rotary compressor, which was laid open on May 7, 2001 with a Korean Patent Publication No. 2001-0035687.
The compressor with a Z-plate in accordance with a conventional art will now be described with reference to FIG. 1.
The conventional compressor with a Z-plate includes an electric mechanism unit consisting of a stator (Ms) and a rotor (Mr) which generate a driving force at an upper portion inside a casing 1 and a compression mechanism unit connected to the rotor (Mr) and sucking, compressing and discharging a fluid.
The compression mechanism unit includes a cylinder 2 fixed at a lower portion of the casing 1, first and second bearing plates 3A and 3B fixed at an upper face and a lower face of the cylinder 2 and forming an inner space of the cylinder 2, a rotational shaft 4 coupled at the rotor (Mr) of the electric mechanism unit and penetratingly coupled at the bearing plates 3A and 3B to transfer a driving force of the electric mechanism unit to the compression mechanism unit, a Z-plate 5 coupled at the rotational shaft 4 or integrally molded to section the inner space of the cylinder 2 into first space (S1) and second space (S2), first and second vanes 6A and 6B of which a lower end and an upper end is respectively in contact with both faces of the Z-plate 5 so as to section each space S1 and S2 into a suction area and a compression area when the rotational shaft 4 is rotated, and first and second spring assemblies 8A and 8B for elastically supporting the vanes 6A and 6B.
With reference to FIG. 2, the Z-plate 5 is formed as a disk type in view of a plane projection so that its outer circumferential face can slidably contact an inner circumferential face of the cylinder 2. When unfolded, the side of the Z-plate 5 forms a curved portion 5a in a sine wave shape.
Both top dead center portions of the Z-plate 5 are in contact with each bearing face of the first bearing plate 3A and the second bearing plate 3B, and the contact portion forms a plane portion 5b so as to enlarge a sealing area by being in surface-contact with the bearing faces of each of the bearing plates 3A and 3B.
The first vane 6A and the second vane 6B are formed as a rectangular parallelepiped, of which each upper end is supported by the spring assemblies 8A and 8B and each lower end penetrates each of the bearing plates 3A and 3B so as to be in contact with both upper and lower sides of the Z-plate 5.
In FIG. 1, reference numerals 2a and 2b are suction passage of each space, 3a and 3b are discharge passages, 7A and 7B are discharge mufflers, 7a and 7b are discharge holes, DP is a discharge pipe, and SP is a suction pipe.
The compressor with the Z-plate in accordance with the conventional art is operated as follows.
When the rotor (Mr) is rotated as power is applied to the electric mechanism unit, the rotational shaft 4 coupled at the rotor (Mr) is rotated in one direction together with the Z-plate 5, and the vanes 6A and 6B being in contact with both upper and lower sides of the Z-plate are reciprocating in the opposite direction, varying a capacity of the first space S1 and the second space S2. In line with this, a fresh fluid is simultaneously sucked through each of suction passages 2a and 2b of the first space S1 and the second space S2, gradually compressed and then discharged through the discharge passages 3a and 3b of the spaces S1 and S2 at the instant when the upper dead center or the lower dead center of the Z-plate 5 reaches the discharge initiation point.
However, in the compressor with the Z-plate in accordance with the conventional art, the portion (θ1, θ2) where the curved portion 5a and the plane portion 5b of the Z-plate 5 meet each other is formed with an edge, so that when the vanes 6A and 6B behave, a minute lifting phenomenon occurs, causing a fluid leakage and an impact noise.
In addition, as the edge portion where the curved portion 5a and the plane portion 5b meet contacts the contact surface of the vanes 6A and 6B or contacts the bearing surface of the bearing plates 3A and 3B, an abrasion occurs due to scratch, and in worst case, a crack is generated between both spaces centering around the plane portion 5b, which would cause a compressed fluid leakage. This would result in a degradation of a compression performance.